Contiguous Leads

[fiznat]

We had a bit of a disagreement in medic class today about contiguous leads, I thought some of you folks here might be able to help out.

Are leads V2 and V3 anatomically contiguous? What about V4 and V5?

We asked the instructor this, and he said that they arent-- but this didnt make sense to a friend and me. V2 looks at a septal part of the heart that is directly adjacent to the anterior part of the heart that V3 looks at. I was under the impression that "directly adjacent to" and "contiguous" meant the same thing. Our instructor maintained that the two leads are not contiguous because they view "different sections" of the heart: IE septal and anterior. We disagree.

Discuss?

[JCicco345]

I just took my cardiology portion last semester and we learner that V2, V3 are contiguous leads as are V4, V5. For the reason you said. V2 and V3 would be anteroseptal, and V4 and V5 would be anterolateral. Atleast thats the way i remember it. I could be wrong.

[Thunderchild145]

We just got done covering this. For the chest leads, they are contiguous. I.E. when looking for Q waves and ST elevation you look for it in pairs, right? Well if you see it in V2 and V3, that counts. V2, V3, and V4 would indicate anteroseptal STEMI/AMI, even if V1 shows nothing.

[fiznat]

Yeah thats pretty much what I thought. ...But not all chest leads are contiguious right? Like, ST elevations in V1 and V4 only would NOT be indicitive of a MI (assuming no other evidence) because they are not contiguious to eachother.

V2 and V3 are contiguous because of the proximity of the anatomical locations viewed by those leads- not simply because they are both "chest leads." Just wanted make sure we're on the same page.

[AZCEP]

Good discussion on a topic that is easy to become confused about.

In the technical definition, contiguous means viewing the same anatomic region. Unfortunately, the heart doesn't have barriers to divide on section from the next.

V1 and V2 are septal, but if the changes present in V2 and V3, you are looking at the anterior wall.

Same holds for V4 --> V5. Yes, V5 is lateral, but when the injury occurs on the intermediary tissue, you have to consider them as contiguous.

Good to see some thinking out there.

[kevkei]

To expand on AZCEP, There are two ways the leads can be contiguous, that is, "anatomically" in any of the leads or "numerically" in the precordial or chest leads.

If you have something showing in leads V2 - V3, this would be numerically contiguous and looks at the anterioseptal aspect of the heart. What if you have anatomically contiguous changes (ST elevation) say in leads I and V6 (or what about aVL?)? Both are looking at the lateral aspect of the left ventricle so you have enough criteria to say there is evidence of injury in two contiguous leads.

[medic5587]

Lateral-- I, AVL, V5, V6

Inferior-- II, III, AVF

Anteroseptal-- V1, V2, V3, Some consider V4 as well

Posterior-- V8, V9

Right Ventricle-- V4R, V5R

Don't forget to back up your STEMI diagnostics with reciprocal changes.